<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <script>
        let a=prompt('银行卡余额')
        let b=prompt('水费')
        let c=prompt('电费')
        let d=prompt('网费')
        let e=a-b-c-d
    </script>
    <table>
        <caption>2020年12月消费支出</caption>
        <tr><th>银行卡余额</th>
        <th>水费</th>
        <th>电费</th>
        <th>网费</th>
        <th>余额</th></tr>
        <tr><td><script>document.write(a)</script></td>
        <td><script>document.write(b)</script></td>
        <td><script>document.write(c)</script></td>
        <td><script>document.write(d)</script></td>
        <td><script>document.write(e)</script></td></tr>
    </table>
</body>
</html>